Leverage system



June 6, 1950 w OSBURN 2,510,651

LEVERAGE SYSTEM Filed July 10, 1944 3 Sheets-Sheet 1 l/k TOF/V EYPatented June 6, 1950 uaireo srAr Es PATENT FElaE i BEVERAGE SYS'EEM,

lfmnardiw. Osburn Detroit; Mich assignor to Power Brake PartsManufacturing and Sales Eompany; Detroit; Mich-., a corporation of"Michigan Applicatiohluly-m, 1944, SerialNo. macs.

' The present invention pertains to a novel forceapplying mechanism andparticularly" to a leverage system for operating such devices as vehiclebrakes, presses and other machines operating by pressure exerted by the.body of the operator In hydraulic brakes for trucks, for example,

physicalv strength of the operator alone is ordinarily in'sufllicientforcsatisfactory operation, and. a booster iscommonly reiniired; Variouspower multiphzingdevices. not requiringa booster tionsr Briefly, theinventionv includes a lever having a progressively increasinamechamcaladvantage by virtue or, aninput lever ridingalong one edge thereon This:edge iszpreferably concave, whereby the displacement. of the lever isreduced and its mcchanm. advantageiurther increased. Then'eeend oi thefirst lever is connected to the load.

invention is subrlect. to various embodimcnts, some or which aredisclosedin the following description and in. the accompanying draw ingsin which Figure l is a side elevation, partly broken away, of a brakeactuator; I V

Figure 2 is a-planview;

Figure 3 is a section on the line 3-4 of Figure 1; r

Figure 4 is a detail of a modification;

Figure'5 isi anrelevaflofi, partly in section; of a press embodying theinvention and Figure 6 is an elevation of the. actuating mechanismtherefor.

Reference to these views will now be made by use of like characterswhich are employed to designate corresponding partsthroughout.

In Figure 1 the numeral I designates theirame structure of a vehicle towhich are attached suitabie brackets 2 and 3 for supporting a brakeactuating mechanism. The mechanism iscontaine'd, inpart, in a housing Lsecured to-the. outer ends of the brackets. Amastcrcylinder irissuitably supported on the vehicle and contains a piston 6 adapted toforce fluid under pressure into the lines of a wheel braking system. Thedetails of this system are not illustrated since they are already wellknown in the art. The invention is concerned with the actuation of thepiston.

A cross shaft Ill within the housing 4 supports a bell crankleverhaving-arr inputarm I? and, an

output arm, 12, the, latter projecting through the top of the housing asshown in Figure 3;, To the exposed end of the arm it are attachedtwoparallel links [3 bya pin H. The links are. braced at intervals bysleeves l5 and bolts I16. Between thcremaining ends of the links ispivotally attachedia threaded push rod l'l bymeans'ofa head [8 thereonheld by a pin It A piston rod 20 is ,adjustably attached tcythe rod [8by suitable. fastenings, 21" and, has its-free end; attached in a flaredsocket 2% formed in the piston 6 and shaped to accommodate the varyingangularity of the piston rod. A bellows 2& encloses the external part ofthe piston rod to prevent. entrance of dust into the. cylinder '5 andhas its ends attached respectively to the cylinder and to the distalend' of the piston rod.

Anotherbrackety 24 secured to the frame carries an axle 25 on which-isiournalled: a pedal level? f high mechanical. advantage'having a longinput arm 2a with. pedal 26 and a short output arm .2L To the output armis pivotally attached a threaded rod 28 on which in turn is, adfustablymounted a forked link 2.9. In the lowerpartof the housing 4 is mounteda. pin l 0'; on, which is lournalled another forked; link 3!! with. itsfree end straddling the lfree end of the link 2.9. Both free endssupport and are. joined by pin 29 carrying a roller 3| that rides on adeveloped cam edge 32 formed on the arm I L v The links l3 aremaintained in a substantially rectilinear path by a. pin 33 carried bythe lever arm 26 and received in slots. 34 in the links, The housing 4is supplied with lubricant througha efltting 35, and leakage around thelink 28 is 1 ar rested byabellows 3G fastened. to the housing 4 and to aremote point on the wars. a l

The edal lever is normally retractedby a spring 3! ioining the arm 2! tothe, bracket -21.

The corresponding movement of. the links it is adjustablylimited by ascrew 38 mounted in a. lug 39 ontherhousing 4 andrcngageable by theexposed end of the arm l2. v

In the embodiment shown in Figure 1; themtial position of the roller 3|is approximately midway between the ends of the'cam edge32.- r As thepedal 26.:on lever 26. is depressed, the roller result is that themechanical advantage reaches its maximum value when the fluid brakingpressure in the master cylinder has been developed to its highest point.The displacement of the pedal 26 is conventional, and within this rangea suflicient braking pressure for a truck can be developed without abooster and without unwieldy lever lengths.

In Figure 4, the roller 3| is guided on an inclined plane 30' ratherthan in an are by a link. The initial position of the roller is nearerthe fulcrum of the arm I l, illustrating in one respect the variabilityof design for difierent installations. As a further variant, the initialportion 32a of the cam edge 32' is a straight line for approximately 22on the prolongation of the-arcu-v ate cam edge, since the increasedmechanical advantage of a concave edge is not needed in the initialmovement of the lever and master cylinder piston, where the brakingpressure is at its minimum.

Figures 5 and 6 show the invention applied to a machine of the presstype such as a punch, straightening press, riveter or the like. Themachine, shownas a bench model, comprises a base 40 on which is erecteda column 4| formed with jaws 42, 43. In the upper jaw 42 is slidablymounted a plunger 44 held in its upper position by a spring 45. In thelower jaws is a threaded, adjustable supporting column 46 locked by anut 41. The plunger 44 is actuated by a rocker 48 pivotally mounted at49 on the jaw 42, and the rocker is actuated by the means that will nowbe described.

In the column 4| is mounted a cylinder 50 containing a piston 5|. Apiston rod 52 is loosely received in the top of the piston and has itsupper end pivoted at 53 to the rear end of the rocker '48. The spring 45tends to depress the piston rod, and this movement is limited by anadjustable bolt 54 mounted upon the jaw 42. The top of the cylinder 50is sealed by a rubber cover 55 that hugs the piston rod. At the base ofthe cylinder is a passage 56 adapted to be uncovered by a portedbl-eeder screw 51.

On the fioor, or conveniently beneath the head of the machine, isprovided a mounting bracket 60 to which is pivotally attached a pedallever .The lever carries an adjustable stop screw 62 adapted to strikeagainst the bracket. To the bracket is also secured a hydraulic mastercylinder 63 of known design and containing a piston 64. The outlet 65 ofthe cylinder 63 is connected by a pipe 66 to a port 6'! in the bottom ofthe cylinder 50., g

A cam lever 68, with a concave cam edge 69,'ls pivotally mounted at onthe bracket 60 between the lever 6| and the cylinder 63. The

proaches the end of its power stroke. As in the 4 braking system, themechanical advantage is relatively low at the beginning of the powerstroke and reaches its maximum when the load is greatest. A highleverage multiplication is derived notwithstanding the relatively shorttravel of the power input member. H i H I A,

In each of the embodiments offthe invention, the first portion of thepower stroke is similar to a cam action. In the latter portion of thestroke, the power multiplication is so high that it has the efiect of awedge action.

Although specificembodiments of the invention have been illustrated anddescribed, it will be understood that various alterations in the details of construction may be made without departing from the scope ofthe invention, as indicated by the appended claims.

What I claim is:

1. A force-applying mechanism comprising a substantially rightangularbell crank lever having a fixed fulcrum and an outer developedcam edge on one leg, another lever having a fixed ful crum and one endadaptedto ride along said edge toactuate the first lever, a rodpivotally attached to the second lever and lying entirely at one side ofthe longitudinal axis of said leg having the cam edge, a force-applyingarm having an intermediate fulcrum and one end pivotally connected tosaid rod, and linkage. connected to the other leg of said bell cranklever.

2. A force-applying mechanism comprising an output lever, a push rodhaving an end adapted to ride along said lever to actuate the same,means for guiding said end, an actuating lever connected to said rod, aload member connected to the free end of the first lever, and means onthe second lever for guiding said member.

3. A force-applying mechanism comprising an output lever, a push rodhaving an end adapted to ride along said lever to actuate the same,means for guiding said end, an actuating lever connected to said rod,- aload member connected to the free end of the first lever; andaslot-andpin connection between said'member and the second lever forguiding said member.

4. A force-applying mechanism comprising an output lever having aconcave edge, a push rod having an end adapted to'ride along said edgeto actuate the lever, means for guiding said end, an actuating leverconnected to said rod, a load member connected to the free end of thefirst lever, and means on the second lever for guiding said member.

HOWARD W. OSBURN.

REFERENCES CITED The following references are of record in the file ofthis patent:

" UNITED STATES PATENTS Number Name Date 688,351 Skidinore Dec.-10, 19011,584,931 Handy et al. -1 May 18, 1926 1,814,632 Rohr L July 14, 19311,887,845 Mitchell l NOV. 15, 1932 2,162,133 Spire June 13, 19392,310,625 Fischer Feb. 9,1943 2,350,002 'Sittert et al. May 30, 19442,351,049

Kaman June 13, 1944

